9.4 Compressible Flows

Compressibility effects are encountered in gas flows at high velocity and/or in which there are large pressure variations. When the flow velocity approaches or exceeds the speed of sound of the gas or when the pressure change in the system ( $\Delta p /p$) is large, the variation of the gas density with pressure has a significant impact on the flow velocity, pressure, and temperature. Compressible flows create a unique set of flow physics for which you must be aware of the special input requirements and solution techniques described in this section. Figures  9.4.1 and 9.4.2 show examples of compressible flows computed using ANSYS FLUENT.

Figure 9.4.1: Transonic Flow in a Converging-Diverging Nozzle

Figure 9.4.2: Mach 0.675 Flow Over a Bump in a 2D Channel

For more information about the theoretical background of compressible flows, see this section in the separate Theory Guide.